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Right choice is (d) 20

The explanation is: Arachidonic ACID is a polyunsaturated FATTY acid containing 20 carbon atoms. This means that its fatty acid CHAIN contains double bonds. Arachidonic acid contains FOUR cis-double bonds.

Right choice is (a) Nature of R group

The best I can explain: BASED on the nature of the R group there are many AMINO acids. HOWEVER, those which occur in proteins are only of twenty types. The R group can be hydrogen, alcohol, ETC.

Correct OPTION is (a) Valine

For explanation I would say: Valine is a neutral amino ACID. Histidine and LYSINE are basic amino acids, having a pH greater than 7, while aspartic acid is an acidic amino acid and has a pH lesser than 7. Valine is HYDROPHOBIC.

Right option is (c) Acid-soluble

Explanation: The tissue is grinded using mortar and pestle in ORDER to HOMOGENIZE it, using trichloroacetic acid. It is then STRAINED through cheesecloth and the filtrate obtained is acid-soluble in NATURE.

Right option is (d) Enzymes take part in the reaction and INCREASE the rate of reaction

Easiest explanation: Enzymes are named after compounds/ CLASS on which they act and their names END with “-ase”. Oxidoreductase reduces few SUBSTRATES whereas oxidizes few other substrates. Enzyme kinetics is GOVERNED by Michael-Menden equation. Enzymes don’t take part in the reaction but increase the rate of reaction.

Correct option is (d) Phospholipids are an EXAMPLE of simple fatty ACIDS

Easy explanation: Lipids are heterogeneous organic compounds comprising of C, H and O. These are water insoluble and RELEASE more energy as compared to carbohydrates. These also ACT as water barrier and messenger and are constituents of plant. Phospholipids are an example of compound fatty acids.

The correct answer is (b) 3

Best explanation: Each nucleotide consists of a pentose sugar, a PHOSPHATE group and a NITROGENOUS base such as adenine, guanine, CYTOSINE, thymine or uracil. They are the building BLOCKS of NUCLEIC acids which are the genetic material.

Correct ANSWER is (b) False

To explain: Fructose is a MONOMER and is also known as fruit sugar. It can form HOMOPOLYMERS of repeating units of fructose joined by GLYCOSIDIC bonds. The homopolymer thus formed is known as inulin.

The correct option is (c) proteins

The explanation: 10 – 15% of the total CELLULAR mass is taken up by proteins. Proteins are SYNTHESIZED in the cytosol by the information present in the nucleic acids. Nucleic acids are the genetic material of the cell.

Correct CHOICE is (a) STARCH

Best explanation: Plant tissues PRODUCE GLUCOSE by the process of photosynthesis. This glucose is converted to starch which is then stored in the plant tissue. It imparts energy to the plant through the process of respiration.

The CORRECT option is (a) Lipids

The EXPLANATION is: When tissue MATTER is homogenized and strained, it separates into an acid soluble pool and an acid insoluble pool. The acid insoluble pool CONTAINS proteins, nucleic ACIDS, polysaccharides and lipids. Out of these, only lipids are not polymeric.

Right option is (B) False

To explain: CAROTENOIDS and anthocyanins are some of the types of pigments. Pigments are included in the SECONDARY metabolites. For example, CHLOROPHYLL is the major pigment responsible for trapping light.

The CORRECT choice is (a) True

Easiest explanation: Essential oils such as lemongrass oil are SECONDARY metabolites. This means that they are not involved in the normal growth and DEVELOPMENT PROCESSES but have other uses in human WELFARE.

Right choice is (d) Nitrogen

Explanation: Oxygen has the highest percentage by weight in the EARTH’s crust, that is, 46.6%. Sodium and MAGNESIUM are also PRESENT in some AMOUNTS. HOWEVER, the percentage by weight of nitrogen is very little.

Right choice is (a) Substituted methanes

Explanation: α-amino acids are ALSO called as substituted methanes. Four SUBSTITUENT groups are occupying the four valency positions. These are HYDROGEN, CARBOXYL group, amino group and a VARIABLE R group.

Right choice is (d) Phospholipids

The best EXPLANATION: The cell membrane is a phospholipid bilayer. The polar phosphorus GROUPS are HYDROPHILIC and FACE outwards while the fatty acid tails are non-polar, hydrophobic and face each other.

The correct answer is (c) Proteins still RETAIN their CHARACTERISTICS as they don’t LOSE their primary structure

Best EXPLANATION: Proteins have a unique structure which might get disrupted with change in pH and temperature. Denaturation leads to loss of SECONDARY, tertiary and quaternary structure.Proteins lose their characteristic if their structure is lost. Proteins are stereospecific to many enzymes.

The correct CHOICE is (d) They are used in the control of bacterial pathogens

To elaborate: Competitive inhibitors inhibits the ACTIVITY of ENZYMES. They are structurally SIMILAR to the substrate. MALONATE is a competitive inhibitor for succinic dehydrogenase. They are used to control pathogens.

Correct choice is (C) 15

For explanation I would say: Pyruvic ACID contains three atoms of carbon. THEREFORE, five molecules of pyruvic acid CONTAIN 15 atoms of carbon. Pyruvic acid is the end product of glycolysis, which is a ten-step metabolic pathway.

The correct option is (c) FORMATION of LACTIC acid from glucose

To elaborate: The conversions of AMINO acids to proteins, glucose to glycogen and ACETIC acid to cholesterol are anabolic PROCESSES. The formation of lactic acid from glucose is a catabolic process and liberates energy.

Correct answer is (C) CATABOLISM

The BEST explanation: Catabolism is a type of destructive metabolism in which larger biomolecules are broken down into smaller MOLECULES via various reactions. Catabolic breakdown of biomolecules involves the RELEASE of energy.

The correct CHOICE is (a) Quaternary

To explain: Hemoglobin POSSESSES four SUBUNITS-TWO alpha subunits and two beta subunits. Since hemoglobin is MADE of more than one subunit or polypeptide chain, it possesses a quaternary structure.

Right choice is (c) PROTEIN helices and right-handed

Explanation: Protein helices are always right-handed. The secondary structure OCCURS in the form of helices and sheets. They are always single stranded and only PARTS of the protein CHAIN is FOLDED into helices.

The correct option is (c) Helix

To explain I WOULD say: IODINE is incorporated into the helix of the starch chain. Starch is a polysaccharide made of glucose monomers. The secondary STRUCTURE of starch is in the form of a helix, where iodine MOLECULES are incorporated.

The correct OPTION is (b) LIPIDS

Explanation: 2% of the total cellular mass is taken up by lipids. In the cell, lipids are predominantly found in the cell membrane and nuclear membrane, where they are present in the FORM of a phospholipid bilayer.

Right choice is (d) Responsible for nitrogen fixation in animals

The BEST EXPLANATION: Sodium and POTASSIUM are responsible for the maintenance of extracellular and intracellular fluids through the osmotic effects of the concentration of these TWO ions. These two ions are also responsible for the maintenance of membrane potential and the transmission of electrical impulses in the NERVE cells.

The correct choice is (a) MANGANESE

Easiest explanation: MITOCHONDRIA are rich in manganese. Molybdenum is necessary for fixation of nitrogen, CATALYSED by the enzyme nitrogenase. Copper occurs in cytochrome oxidase.

Right OPTION is (d) Alanine

The best explanation: Amino acids have a chiral CARBON BOUND with an amino GROUP, an acid group, a hydrogen and an R group. In alanine, the R group is a methyl group. In glycine, the R group is a hydrogen atom.

The CORRECT choice is (b) CHEMICAL properties

Explanation: Analytical techniques are used to determine the probable structure and approximate MOLECULAR FORMULA of compounds. Various CONFORMATIONS of a structure can also be determined but chemical properties cannot be determined.

Right choice is (b) The general formula of all carbohydrates is Cx(H20)y

Easiest explanation: Carbohydrates derive its name from the HYDRATES of carbon. Earlier, carbohydrates are assumed to OBEY the formula Cx(H20)y but LATER most of the carbohydrates. Carbohydrates are defined as optically ACTIVE polyhydroxy aldehydes or ketones or the compounds that produce such units on hydrolysis. Glyceraldehyde is the smallest CARBOHYDRATE.

The correct choice is (C) 16

Easiest explanation: Glucose is converted to PYRUVIC acid VIA a metabolic PATHWAY known as glycolysis. 1 MOLECULE of glucose yields 2 molecules of pyruvic acid. Thus, 8 molecules of glucose yield 16 molecules of pyruvic acid.

Right answer is (c) Enzymes

Easy explanation: Biocatalysts are substances that speed up or CATALYZE the RATE of metabolic reactions. Enzymes are KNOWN as biocatalysts as they speed up metabolic reactions without GETTING depleted. They are PROTEINS.

Right OPTION is (c) Secondary

The BEST explanation: Beta SHEETS and alpha helices are forms of the secondary LEVEL of organization of proteins.

Right answer is (d) amino ACIDS

To explain I would say: Proteins are heteropolymers made of amino ACID MONOMERS. There are 21 amino acids. VARIOUS numbers and combinations of amino acids in a sequence or chain FORMS different types of proteins.

The correct option is (a) Chitin

Explanation: Chitin is the main CONSTITUENT of the EXOSKELETON of arthropods and also of fungal cell WALLS. It is a COMPLEX polysaccharide. CELLULOSE makes up plant cell walls, glycogen is a storage polysaccharide in animals while starch is the storage polysaccharide in plants.

The correct answer is (c) Glycogen

Easy explanation: Glycogen is a HOMOPOLYMER of glucose monomers. It is HIGHLY branched. SUCROSE is a disaccharide. Cellulose and chitin are both polysaccharides but they are unbranched or LINEAR in structure.

Correct OPTION is (c) Riboflavin

Easiest explanation: The macromolecular fraction of the CELL consists of polynucleotides or NUCLEIC acid, polypeptides and polysaccharides which are carbohydrates. All of their molecular WIGHTS are above 10,000 Da.

Right OPTION is (a) It is the second most ABUNDANT organic POLYMER

Easiest explanation: CELLULOSE is a homopolymer of repeating glucose UNITS joined to each other by glycosidic bonds. Cellulose chains are linear in structure. Cellulose is the most abundant organic polymer on Earth.

Correct CHOICE is (c) glucose

The explanation: Cellulose is a homopolymer. This means that its chain consists of REPEATING UNITS of a single type of MONOMER. Repeating units of glucose joined by GLYCOSIDIC bonds form the polymer cellulose.

Correct ANSWER is (b) Plants

The explanation is: Starch is present as a STOREHOUSE of energy in the plant tissues. Starch FORMS helical secondary structures which can hold iodine molecules in the helical portions. THEREFORE, the starch-iodine is BLUE.

Right answer is (b) Lipids

Easiest explanation: The acid-insoluble FRACTION, has only four types of organic compounds, i.e., PROTEINS, NUCLEIC acids, polysaccharides and lipids. These classes of compounds except for lipids have molecular weights in the range of ten THOUSAND Daltons and above.